645009 ÷ 7 
The aim is to understand the frequency of 7 in 645009.

Going ahead to step 1:
If we divide 6 by 7, we get 0 and a remainder of 6.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
If we subtract 0 from 6, we get 6.
Bring next digit (4) of the dividend behind the 6 and repeat the process: 64 / 7

Moving on to step 2:
64 divided by 7 is 9 with a remainder of 1.
Record the quotient 9 as the next digit in the result. 
Result so far: 9.0
Deduct 63 from 64 and we're left with 1.
Bring next digit (5) of the dividend behind the 1 and repeat the process: 15 / 7

Moving on to step 3:
15 divided by 7 is 2 with a remainder of 1.
Write down 2 as next digit of the result. 
Result so far: 92.0
Subtracting 14 from 15 leaves us with 1.
Append the next digit (0) from the dividend to 1 and continue with: 10 / 7

Step 4:
7 goes into 10 1 times with a remainder of 3.
Put 1 as the next digit of the answer. 
Result so far: 921.0
Subtract 7 from 10 to get 3.
Fetch the next digit (0) from the dividend, attach it to 3 and continue: 30 / 7

Advancing to step 5:
When dividing 30 by 7, we get 4 with a remainder of 2.
Put 4 as the next digit of the answer. 
Result so far: 9214.0
Deduct 28 from 30 and we're left with 2.
Take the next digit (9) from the dividend and append it to 2, then repeat: 29 / 7

Let's proceed to step 6:
If we divide 29 by 7, we get 4 and a remainder of 1.
The number 4 becomes the next digit in our result. 
Result so far: 92144.0
Deduct 28 from 29 and we're left with 1.
Since there are no more digits in the dividend, we add a zero to the remainder making it 10, and continue the process.

Moving on to step 7:
10 divided by 7 is 1 with a remainder of 3.
Put 1 as the next digit of the answer. 
Result so far: 92144.1
Subtracting 7 from 10 leaves us with 3.
Since there are no more digits in the dividend, we add a zero to the remainder making it 30, and continue the process.

Let's proceed to step 8:
When dividing 30 by 7, we get 4 with a remainder of 2.
The next digit of our result is 4. 
Result so far: 92144.14
Subtract 28 from 30 to get 2.
Since there are no more digits in the dividend, we add a zero to the remainder making it 20, and continue the process.

Advancing to step 9:
7 goes into 20 2 times with a remainder of 6.
The number 2 becomes the next digit in our result. 
Result so far: 92144.142
The remainder is 6 after subtracting 14 from 20.
Since there are no more digits in the dividend, we add a zero to the remainder making it 60, and continue the process.

Step 10:
60 divided by 7 is 8 with a remainder of 4.
Use 8 as the next digit of our solution. 
Result so far: 92144.1428
If we subtract 56 from 60, we get 4.
Since there are no more digits in the dividend, we add a zero to the remainder making it 40, and continue the process.

Moving on to step 11:
If we divide 40 by 7, we get 5 and a remainder of 5.
Write down 5 as next digit of the result. 
Result so far: 92144.14285
Subtracting 35 from 40 leaves us with 5.
Since there are no more digits in the dividend, we add a zero to the remainder making it 50, and continue the process.

Let's proceed to step 12:
7 can be fit into 50 7 times, resulting in a remainder of 1.
The next digit of our result is 7. 
Result so far: 92144.142857
If we subtract 49 from 50, we get 1.
Since there are no more digits in the dividend, we add a zero to the remainder making it 10, and continue the process.

Moving on to step 13:
7 can be fit into 10 1 times, resulting in a remainder of 3.
Put 1 as the next digit of the answer. 
Result so far: 92144.1428571
Deduct 7 from 10 and we're left with 3.
Since there are no more digits in the dividend, we add a zero to the remainder making it 30, and continue the process.

Moving on to step 14:
The number 7 fits into 30 4 times, leaving a remainder of 2.
The next digit of our result is 4. 
Result so far: 92144.14285714
Subtract 28 from 30 to get 2.
Since there are no more digits in the dividend, we add a zero to the remainder making it 20, and continue the process.

After the division, we end up with 92144.14285714 and a remainder of 2e-09.